The invention relates to a heat-insulating walling with an outer casing that is vacuum-tight and with an inner lining spaced from the latter that is vacuum-tight. The inner lining and the outer casing are vacuum-tightly connected to one another by a connecting profile. The connecting profile has an at least approximately U-shaped cross section and has a diaphragm-like base. The connecting profile, together with the outer casing and the inner lining, surrounds an interspace filled with heat-insulation material.
Throughout the application, terms such as xe2x80x9cvacuum tightxe2x80x9d should be read with the understanding that perfect vacuums and perfect seals can never be achieved. However, within the scope of the invention, these terms are to mean as perfect as practicable for the materials, applications, and conditions. German Published, Non-Prosecuted Patent Application DE 197 45 861 A1, which corresponds to U.S. Pat. No. 6,029,846 A, discloses a heat-insulating walling based on vacuum-insulation technology. The heat-insulating walling is for use in a refrigerator housing, a refrigerator door, or a muffle used in a domestic stove. The vacuum-insulating walling known from this publication possesses two cladding walls that are manufactured, for example, from high-grade steel and are vacuum tightly connected to one another by a connecting profile disposed at their free edges and built with a U-shaped cross section. For the vacuum-tight connection, the legs of the u-profile are welded to the free ends of the cladding walls, parallel to these, for example by a beam-welding method. Clamping and supporting tools are necessary for the welding operation, in particular so that the components to be welded to one another are braced suitably for welding purposes. These tools are to be introduced between the legs of the U-shaped connecting profile when the welding operation is being carried out, in order, on the one hand, to absorb the bracing forces of the components to be welded and, on the other hand, to prevent an excessive deformation of the components at their connection point. Although these measures ensure a process-consistent satisfactory manufacture of the heat-insulating housings and doors initially mentioned, the measures are complicated in manufacturing terms and therefore cost-intensive. Moreover, in this type of attachment of the U-shaped connecting profile, the space between the legs of the connecting profile has to be filled with heat-insulation material in order to avoid unnecessary heat or cold losses.
It is accordingly an object of the invention to provide a heat-insulating walling that overcomes the hereinaforementioned disadvantages of the heretofore-known devices of this general type and that improves heat-insulation walling in a simple construction.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a heat-insulating walling. The heat insulating walling includes an as far as possible vacuum-tight outer casing, an as far as possible vacuum-tight inner lining spaced from the outer casing; a connecting profile vacuum-tightly connecting the inner lining and the outer casing; and heat-insulation material filling the interspace. The connecting profile has an at least approximately U-shaped cross section with legs and having a diaphragm-like base. The connecting profile, together with the outer casing and the inner lining, surround an interspace. The U-shaped connecting profile engages with the legs over the outer casing and the inner lining. The legs are vacuum-tightly secured to the inner lining and the outer casing.
This object of the invention is achieved by engaging the U-shaped connecting profile with its legs over the outer casing and the inner lining, and in that, the legs are vacuum-tightly secured to the inner lining and the outer casing.
According to the invention, the connecting profile is fastened in such a way that, in the fastening state of the profile, its legs bear with their inside on the outside of the outer casing and of the inner lining and are vacuum-tightly secured to the sides, for example by welding or adhesive bonding. This configuration prevents an interspace, such as those that occurs when the U-shaped connecting profile is attached in the conventional way and has to be filled with heat-insulation material to prevent heat-insulation losses. Furthermore, a possible risk of injury to the manufacturing personnel in the handling of the heat-insulating walling during its manufacturing is eliminated by virtue of the cap-like covering of the sharp-edged free margins of the inner lining or of the outer casing by the U-shaped connecting profile. Such risks are caused by the sharp edges produced when the outer casing or the inner lining are produced at the margins of these. Moreover, no tools are required to support the clamping forces occurring when the outer casing or the inner lining is braced by the legs of the U-shaped connecting profile suitably for welding purposes when an open-celled heat-insulation material of increased pressure resistance is used. The open-celled heat-insulation material of increased pressure can be, for example, an open-celled polymer foam, such as polystyrene foam sold under the trademark DOW INSTILL(copyright). The open-celled heat-insulation material is pressed in order to increase the pressure resistance at an increased temperature that is above the glass temperature. As compared to the prior art, the U-shaped connecting profile slipped over the free ends of the outer casing and of the inner lining optimizes the heat-insulating wallings, because the wallings now possess a top-value heat-insulation capacity even at the connection point of their outer cladding walls.
According to a preferred embodiment of the subject of the invention, there is provision for a backing part to be provided on the inner lining and the outer casing, on the heat-insulation side, at least approximately over the length and height of the legs of the U-shaped connecting profile.
A backing part ensures that the heat occurring during the operation of welding the legs of the U-shaped connecting profile to the outer casing and the inner lining is as far as possible shielded from the open-celled heat-insulation material produced as a supporting body between the outer casing and the inner lining. As a result, the process management of the welding operation, to be precise the through-welding indispensable for the vacuum-type connection of the connecting profile to the outer casing or the inner lining, becomes markedly easier.
In accordance with a further object of the invention, a backing part for shielding the welding heat has been shown to be particularly beneficial. Welding heat is produced while welding the open-celled heat-insulation material introduced as a supporting body between the outer casing and the inner lining. The backing part has been shown to be particularly beneficial in terms of heat shielding, on the one hand, and of the execution of the welding process, on the other hand, when the backing element contains a high-grade steel strip or an aluminum strip with a material thickness having at least the material thickness of the outer casing or of the inner lining. Good heat shielding results have been shown even with material thicknesses of the order of one millimeter (1 mm).
In accordance with a further object of the invention, the U-shaped connecting profile for connecting the outer casing and the inner lining can be composed of a plurality of longitudinal portions. Ends of the longitudinal portions forming the joints are connected to one another as far as possible in a vacuum-tight manner.
Owing to the possibility that the connecting profile can be vacuum-tight fastened in portions between the inner lining and the outer casing along the margins to be connected, the production of the vacuum-tight connection, for example produced by adhesive bonding or welding, is considerably simplified. The simplification markedly reduces the manufacturing costs for the heat-insulating walling.
In accordance with a further object of the invention, U-shaped supporting elements can be provided on the joints. The U-shaped supporting elements bridges at least one of the joints. The ends of the U-shaped connecting parts lie on the U-shaped supporting elements and are connected in airtight manner. The end portions of the individual longitudinal portions are inserted one into the other along the margins of the outer casing and of the inner lining. Accordingly, the end portions can be vacuum-tight connected to one another with particular process consistency. The supporting elements serve as a bearing from the diaphragm-like base of the connecting profiles. Simultaneously, the support elements make the vacuum-tight connection of the ends of the longitudinal portions of the joints easier.
In accordance with a further object of the invention, the U-shaped supporting element can be secured with its legs to the inner lining and the outer casing on the heat-insulation side. Accordingly, U-shaped supporting elements can be more-easily secured to the outer casing, on the one hand, and the inner lining, on the other hand.
In accordance with a further object of the invention, the U-shaped connecting profile can be covered by a U-shaped covering profile that engages with its legs over the legs of the connecting profile and is held on the latter. By virtue of the U-shaped configuration of the covering profile, the connecting profile is protected both by its legs, vacuum-tightly secured to the outer casing and to the inner lining, for example by welding or adhesive bonding, and on its impact-sensitive diaphragm-like base.
In accordance with a further object of the invention, the covering profile can have holders for holding it. The holders can hold the covering profile with its base at a distance from the base of the connecting profile to form a receiving space.
By providing an interspace between the impact-sensitive base of the connecting profile and the base of the covering profile, the connecting profile is protected even in the event of relatively high impact load on the covering profile. Moreover, the interspace makes it possible in a space-saving and aesthetic way to attach and accommodate further functional parts, for example an anchor for a magnetic seal used in a refrigerated door, or a heating line for preventing condensation from forming in a refrigerator housing in the region of its access opening.
In accordance with a further object of the invention, the holder on the covering profile can be configured as holding strips disposed on the inside of its legs at a distance corresponding to the height of the connecting profile. Accordingly, the covering profile is held particularly accurately in position in terms of the formation of the receiving space.
In accordance with a further object of the invention, the receiving space can serve for introducing a line-like heating device held on the covering profile. As a result, the line-like heating device is disposed particularly inconspicuously and particularly favorably in terms of the introduction of heat to prevent condensation from forming in a refrigerator housing at its access opening.
In accordance with a further object of the invention, the inner lining, the outer casing, and the connecting profile are formed from thin-walled high-grade steel or aluminum-coated plastic. As a result, a heat-insulating walling is formed that is particularly robust and resistant with regard to maintaining the vacuum generated between the outer casing and the inner lining.
In accordance with a further object of the invention, the door and/or housing of a refrigerator include a heat-insulating walling as described above. The refrigerator will have improved heat-insulation capacity in relation to the insulating wall thicknesses necessary for this purpose.
In accordance with a further object of the invention, a domestic stove including a heat-insulating muffle surrounding a baking space can have a heat-insulating walling. The stove has increased heat-insulation capacity in light of the thickness of the heat-insulating wallings that are to be employed for this purpose.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a heat-insulating walling, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.